21210640026 has 16 divisors (see below), whose sum is σ = 42691481184. Its totient is φ = 7025179824.

The previous prime is 21210640021. The next prime is 21210640081. The reversal of 21210640026 is 62004601212.

It is a junction number, because it is equal to n+sod(n) for n = 21210639978 and 21210640005.

It is not an unprimeable number, because it can be changed into a prime (21210640021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11257360 + ... + 11259243.

It is an arithmetic number, because the mean of its divisors is an integer number (2668217574).

Almost surely, 2^21210640026 is an apocalyptic number.

21210640026 is an abundant number, since it is smaller than the sum of its proper divisors (21480841158).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21210640026 is a wasteful number, since it uses less digits than its factorization.

21210640026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22516765.

The product of its (nonzero) digits is 1152, while the sum is 24.

The spelling of 21210640026 in words is "twenty-one billion, two hundred ten million, six hundred forty thousand, twenty-six".